Timing circuit with means for selectively alternating the timing pulses



Nov. 30, 1965 JACOBS 3,221,174

TIMING CIRCUIT WITH MEANS FOR SELECTIVELY ALTERNATING THE TIMING PULSESFiled June 4, 1962 L N ox K x/54 3 Fig.

Fig. 2

INVENI'OR. James W Jacobs His Af/ome y United States Patent MotorsCorporation, Detroit, Mich, a corporation of Delaware Filed June 4,1962, Ser. No. 129,806 11 Claims. (Cl. 3ti7-41) This invention relatesto a domestic appliance and more particularly to an appliance timer withmeans for selectively altering the timing impulses.

The automatic operation of many appliances is controlled by timers and,thus, the complexity of these timers 1s a matter of concern in thedevelopment of low cost dependable products. One of the more commontiming arrangements on the market today involves the use of andescapement mechanism with a drive motor to intermlttently advance aplurality of cams for sequentially controlling a timed cycle. In view ofthe cost and complexity of escapement mechanisms, it is a general objectof this nvention to provide an automatic appliance timer which isextremely accurate as well as simple to construct and operate.

A further object of this invention is the provision of a transistordiode timing circuit with means for selectively varylng the timing rateof said circuit in accordance with the voltage of power supplied to saidcircuit.

Another object of this invention is the provision of a timer 11511] g atransistor diode timing circuit with means for automatically changingthe voltage of power supplied to said timlng circuit, thereby to alterthe timing rate of said timer during the timed cycle.

It is broadly an object of this invention to selectively vary the timingrate of a timer in accordance with voltage supplied to said. timer.

Further objects and advantages of the present invention will be apparentfrom the following description, reference bemg had to the accompanyingdrawings wherein prefgrred embodiments of the present invention areclearly s own.

In the drawings:

FIGURE 1 is a schematic wiring diagram of a timer. the timing rate ofwhich is shifted automatically in accord ance with voltage supplied tothe timer; and

FIGURE 2 is a schematic wiring diagram of another embodiment of thisinvention wherein the timing rate is manually selectable.

In accordance with this invention and with reference to FIGURE 1, atimer is shown interposed between a 23Q volts AC. or 115 volts AC. powersupply, generally designated as L L and N. The timer 10 is adapted tosequence a plurality of loads 12 and 14. These loads could be componentsof a domestic appliance such as the fill valve and drive motor in aclothes washer. Although both loads 12 and 14 are shown connected across230 volts, it should be understood that the loads could be connectedequally as well to the smaller voltage 115- volt supply or selectivelyto either supply.

The timer 10 is comprised of a transistor diode timing circuit 16including a four-layer hyper-conductive negative resistance transistordiode 18, a capacitor 20, and an actuator or solenoid coil 22. Theactuator coil 22 is in series with the diode 18 while both the coil 22and the diode 18 are in parallel with the capacitor 20. The timlngcircuit formed by conductors 24, 26, the diode 18, the actuating coil 22and the capacitor 20 form the parallel timing circuit 16 which iscapable of providing intermittent timing pulses through the coil 22 forrepeatedly advancing a plurality of timer cams 28, and 32 byincrementally rotating a shaft 40 to which the cams are 3,221,174Patented Nov. 30, 1965 Ice attached. More particularly, the cams areintermittently roated through a ratchet wheel 34 arhxed to the shaft 40and a pawl 36the pawl being actuated whenever the coil 22 is energized.A return spring 38 may be connected to a fixed structure to return thepawl whenever the coil 22 is deenergized.

In series with the timing circuit 16 is a resistance 42 and a rectifierdiode 44these components being in series with a cam actuated voltageselector switch 46 movable between a high voltage contact 48 and a lowvoltage con tact 50. The firing rate of the coil 22 on a given voltagemay be predetermined in accordance with the size of the resistance 42,but this firing rate is alterable in accordance with the voltageconnection of the cam actuated switch 46. Thus, when the switch 45 isconnected to the contact 51 the timing circuit 16 is; energized from the115-volt power supply and the timing rate is approximately one-half thataccomplished when the switch 46 is energized through the high voltagecontact 43. In other words, the firing rate of the timing circuit 16varies linearly with its voltage supply.

For a common 115-230-volt alternating current power source, the diode 18may, for example, have a switching or breakdown voltage of about volts.One suitable diode may be a four-layer PNPM germanium diode, such as theWestinghouse WX Dynistor which has voltage current characteristicsproviding for a certain breakdown or switching action, assuming, ofcourse, that the peak voltages of the power supply are greater than theswitching voltage of the diode. In the one direction of flow, thecurrent will flow through the diode 18 with little resistance. Thecurrent flow, however, is in the direction of flow opposite to thedirection of flow permitted by the rectifier 44 so that the current flowwill be extremely limited. In the opposite direction, the current flowwill be substantially prevented until the breakdown voltage is reached.The breakdown voltage, if exceeded, permits peak currents of severalamperes with little resistance and this is sufficient to operatesolenoid actuators which can operate the pawl and ratchet 34, 36.

In operation, assume that a master line switch 54 is closed to energizethe timer 10. With the circuitry shown in FIGURE 1, -volt AC. power issupplied through the low voltage contact 50 to the rectifier diode 44,the resistor 42 and then the capacitor 20 to the other side of the lineL This provides pulses of rectified A.C. current to the capacitor. Thecapacitor gradually builds up a charge as permitted by the RC timeconstant until a sufficient voltage is reached to cause the four-layerdiode 13 to breakdown and avalanche, thereby discharging the capacitorthrough the actuating coil 22. Each pulse of the coil 22 causes the cams28, 30 and 32 to index or advance. With the cam arrangement illustratedin FIGURE 1, the load 12 would be energized from L cam switch 31, theload 12 to the other side of the line L Since cam switch 33 is open,load 14 will be deenergized during this portion of the control cycle. Ata predetermined point in the controlled cycle during one oftheincremental advances, cam 28 will cause the voltage selector switch 46to shift from the low voltage contact 50 to the high voltage contact 48and the timing circuit 16 will be energized from 230-volt power supplyinstead of 115-volt. This, in effect, doubles the firing rate of thecoil 22 and causes the cams 28, 30 and 32 to advance more rapidly.During the last portion of the timing cycle illustrated, the cam switch31 for load 12 will be opened while the switch 33 for load 14 will beclosed. In this situation and even though the cams 28, 30 and 32 aredesigned with equal segments devoted to the control of their respectiveloads, the load 14 will be energized only half as long as load 12.

In the foregoing embodiment, the speed or firing rate of the timer wasautomatically changed during the course of the cycle controlled. Turningnow to FIGURE 2, there is shown a timer 6% having the same timingcircuit 16 and a cam 62 for operating the switch 64 in series circuitrelationship with a load 66. The embodiment of FIGURE 2 varies over thatin FIGURE 1 in that a manual cycle speed selector 68 is interposedbetween the power supply and the timer 60. The speed selector includes aswitch 70 operating between the low voltage contact 50 and the highvoltage contact 48. Thus, whenever the operator wishes to operate theload 66 for a short period of time, the switch 70 may be set against thehigh voltage contact 48. In this manner, the timing circuit 16 will firethe coil 22 approximately twice as often as would occur if the switch 70were against the low voltage contact 50, assuming a 1l5-volt-230-voltpower supply. Should different timing rates be desired, it is wellwithin the skill of the art to provide voltage varying means to achievethe precise firing rate needed in the timer. The RC time constant ofresistance 42 and capacitcr may also be predetermined for this purpose.

It should now be seen that an improved electrical timing device has beendeveloped wherein the voltage of the power supply may be used to alterthe timing pulses of the timer. These alterations can be made manuallyto select a longer or shorter duration for a given cycle portion or theycan be made automatically by the timer itself, thereby to alter theduration of selected portions of a complete timing cycle. The foregoingexplanation with reference to the timing circuit is believed sufficientfor an understanding of this invention. However, for additional detailson the theory of the transistor diode timing circuit, reference may behad to the assignees copending application, Serial No. 71,581.

While the embodiments of the present invention as herein disclosedconstitute preferred forms, it is to be understood that other formsmight be adopted.

What is claimed is as follows:

1. In combination with a first and second load to be sequenced and analternating current power supply having a first peak output voltageconductor and a second peak output voltage conductor, a timer comprisinga first contact connected to said first voltage conductor and second,third and fourth contacts connected to said second voltage conductor,said first and second load being energized respectively through saidthird and fourth contacts, first, second and third switch means forsequentially electrically engaging said contacts, said first switchmeans engageable with said first or second contact, said second switchmeans connected to one side of said first load and engageable with saidthird contact, said third switch means connected to one side of saidsecond load and engageable with said fourth contact, and means formoving said switch means including a cam shaft connected to said switchmeans, means for rotating said cam shaft and timing means forintermittently actuating said rotating means, said timing meansincluding an actuator coil for actuating said rotating means, a negativeresistance diode connected in series with said actuator coil, said diodehaving a predetermined switching voltage, a capacitor connected in aparallel circuit with the actuator coil and diode, said capacitor beingcapable of being charged to a voltage great enough to exceed theswitching voltage of said diode, a rectifier connected in series withsaid first switch means and one side of said parallel circuit andoriented to prevent flow of current through said diode before said dodereaches its switching voltage, circuit means connected to the othersides of said parallel circuit and said first and second loads forcompleting a circuit with said power supply, said peak output voltagesof said power supply being greater than the switching voltage of saiddiode for selectively supplying energy to said rectifier and saidparallel circuit for repeatedly operating said actuator coil at onefrequency when said first switch means is engaged with said firstcontact and at another frequency when said first switch means is engagedwith said second contact.

2. In combination with a first and second load to be sequenced and analternating current power supply having a low output voltage conductorand a high output voltage conductor, a timer comprising a first contactconnected to said low voltage conductor and second, third and fourthcontacts connected to said high voltage conductor, said first and secondload being energized respectively through said third and fourthcontacts, first, second and third switch means for sequentiallyelectrically engaging said contacts, said first switch means engageablewith said first or second contact, said second switch means connected toone side of said first load and engageable with said third contact, saidthird switch means connected to one side of said second load andengageable with said fourth contact, and means for moving said switchmeans including a cam shaft connected to said switch means, pawl andratchet means for rotating said cam shaft and timing means forintermittently actuating said pawl and ratchet means, said timing meansincluding an actuator coil for actuating the pawl of said pawl andratchet means, a negative resistance diode connected in series with saidactuator coil, said diode having a predetermined switching voltage, acapacitor connected in a parallel circuit with the actuator coil anddiode, said capacitor being capable of being charged to a voltage greatenough to exceed the switching voltage of said diode, a rectifierconnected in series with said first switch means and one side of saidparallel circuit and oriented to prevent flow of current through saiddiode before said diode reaches its switching voltage, circuit meansconnected to the other sides of said parallel circuit and said first andsecond loads for completing a circuit with said power supply, said highand low output voltages of said power supply being greater than theswitching voltage of said diode for selectively supplying energy to saidrectifier and said parallel circuit for repeatedly operating saidactuator coil at low frequency when said first switch means is engagedwith said first contact and at high frequency when said first switchmeans is engaged with said second contact.

3. In combination with a load to be controlled and an alternatingcurrent power supply having a first voltage conductor and a secondvoltage conductor, a timer speed selector switch having a first positionin engagement with said first voltage conductor and a second position inengagement with said second voltage conductor, a timer comprising acontact connected to one of said voltage conductors, said load beingenergized through said contact, switch means connected to one side ofsaid load for selectively electrically engaging said contact and meansfor moving said switch means including a cam shaft means connected tosaid switch means, means for rotating said cam shaft means and timingmeans for intermittently actuating said rotating means, said timingmeans including an actuator coil for actuating said rotating means, anegative resistance diode connected in series with said actuator coil,said diode having a predetermined switch voltage, a capacitor connectedin a parallel circuit with the actuator coil and diode, said capacitorbeing capable of being charged to a voltage great enough to exceed theswitching voltage of said diode, a rectifier connected in series withsaid timer speed selector switch and one side of said parallel circuitand oriented to prevent flow of current through said diode before saiddiode reaches its switching voltage, means connecting the other side ofsaid parallel circuit and said load for completing a circuit with saidpower supply, said voltages of said power supply being greater than theswitching voltage of said diode for supplying energy to said rectifierand said parallel circuit for repeatedly operating said actuator coil atOne frequency when said timer speed selector switch is in said firstposition and at another frequency when said timer speed selector switchis in said second position.

4. The combination of claim 3 wherein said timer speed selector switchis moved between said first and second positions by said cam shaftmeans.

5. The combination of claim 3 wherein said timer speed selector switchis manually movable between said first and second positions.

6. In combination, an electrical timing device comprising a drivingmeans, a driven means connected to said driving means for controllingthe multiple functions of a timing cycle, a power source having high andlow voltage conductors, means selectively connected to the high or lowvoltage conductor of said power source by said driven means forperiodically actuating said driving means to intermittently advance saiddriven means through the multiple functions of said cycle, saidactuating means including means responsive to the voltage of theconductor connected to said actuating means for determining the periodof intermittency of said driving means thereby to control the durationof each of said multiple functions.

7. In combination, an electrical timing device comprising a drivingmeans, a driven means connected to said driving means for controllingthe multiple functions of a timing cycle, a power source having high andlow voltage conductors, means selectively connected to the high or lowvoltage conductor of said power source for periodically actuating saiddriving means to intermittently advance said driven means through themultiple functions of said cycle, said actuating means including meansresponsive to the voltage of the conductor connected to said actuatingmeans for determining the period of intermittency of said driving meansthereby to control the duration of said timing cycle.

8. In combination with a load energizable in a timed cycle, timer switchmeans in power supply relationship to said load actuatable to energizesaid load in a timed cycle for a long or short interval, an electricaltiming device comprising a driving means, a driven means advancedlyconnected to said driving means and actuatably related to said timerswitch means for controlling said timed cycle by actuating said timerswitch means, a power source having a low output voltage conductor and ahigh output voltage conductor, actuating means selectively connectableto the low and high output voltage conductors of said power source forperiodically actuating said driving means to intermittently advance saiddriven means during said timed cycle, said actuating means includingmeans responsive to the voltage of the conductor connected to saidactuating means for determining the period of intermittency of saiddriving means thereby to control the duration of said time cycle, andmeans for completing a circuit with said actuating means and said load,said load being energized for said long interval when said actuatingmeans is connected to said low output voltage conductor, and said loadbeing energized for said short interval when said actuating means isconnected to said high output voltage conductor.

9. The combination of claim 8 wherein said voltage responsive meansincludes an actuator coil operably connected to said driving means, anegative resistance diode in series with said actuator coil, a capacitorconnected in a parallel circuit with said actuator coil and diode, arectifier in series with said parallel circuit and a resistance inseries with said rectifier.

10. The combination of claim 8 wherein said voltage responsive meansincludes an actuator coil operably connected to said driving means,semi-conductor switch means in series with said actuator coil, capacitormeans connected in a parallel circuit with said actuator coil andsemi-conductor switch means, rectifier means in series with saidparallel circuit and resistance means in series with said rectifiermeans.

11. In combination with a load to be controlled and an alternatingcurrent power supply having a first voltage conductor and a secondvoltage conductor, a timer speed selector switch having a first positionin engagement with said first voltage conductor and a second position inengagement with said second voltage conductor, a timer comprising acontact connected to one of said voltage conductors, said load beingenergized through said contact, switch means connected to one side ofsaid load for selectively electrically engaging said contact and meansfor moving said switch means including actuator means drivably connectedto said switch means, means for operating said actuator means and timingmeans for intermittently actuating said operating means, said timingmeans including an actuator coil for actuating said operating means, anegative resistance diode connected in series with said actuator coil,said diode having a predetermined switch voltage, a capacitor connectedin a parallel circuit with the actuator coil and diode, said capacitorbeing capable of being charged to a voltage great enough to exceed theswitching voltage of said diode, a rectifier connected in series withsaid timer speed selector switch and one side of said parallel circuitand oriented to prevent flow of current through said diode before saiddiode reaches its switching voltage, means connecting the other side ofsaid parallel circuit and said load for completing a circuit with saidpower supply, said voltages of said power supply being greater than theswitching voltage of said diode for supplying energy to said rectifierand said parallel circuit for repeatedly operating said actuator coil atone frequency when said timer speed selector switch is in said firstposition and at another frequency when said timer speed selector switchis in said second position.

References Cited by the Examiner UNITED STATES PATENTS 2,444,210 6/1948Lauricella 3074l X 2,948,837 8/1960 Postal 33ll07 3,030,523 4/1962Pittman 307--88.5

OTHER REFERENCES Thompson, R.: An Audio-Frequency Rectifiers, TheInstitution of Electrical Engineers Paper No. 3889B May 1962.

LLOYD MCCOLLUM, Primary Examiner.

1. IN COMBINATION WITH A FIRST AND SECOND LOAD TO BE SEQUENCED AND ANALTERNATING CURRENT POWER SUPPLY HAVING A FIRST PEAK OUTPUT VOLTAGECONDUCTOR AND A SECOND PEAK OUTPUT VOLTAGE CONDUCTOR, A TIMLERCOMPRISING A FIRST CONTACT CONNECTED TO SAID FIRST VOLTAGE CONDUCTOR ANDSECOND, THIRD AND FOURTH CONTACTS CONNECTED TO SAID SECOND VOLTAGECONDUCTOR, SAID FIRST AND SECOND LOAD BEING ENERGIZED RESPECTIVELYTHROUGH SAID THIRD AND FOURTH CONTACTS, FIRST, AND SECOND AND THIRDSWITCH MEANS FOR SEQUENTIALLY ELECTRICALLY ENGAGING SAID CONTACTS, SAIDFIRST SWITCH MEANS ENGAGEABLE WITH SAID FIRST OR SECOND CONTACT, SAIDSECOND SWITCH MEANS CONNECTEAD TO ONE SIDE OF SAID FIRST LOAD ANDENGAGEABLE WITH SAID THIRD CONTACT, SAID THIRD SWITCH MEANS CONNECTED TOONE SIDE OF SAID SECOND LOAD AND ENGAGEABLE WITH SAID FOURTH CONTACT,AND MEANS FOR MOVING SAID SWITCH MEANS INCLUDING A CAM SHAFT CONNECTEDTO SAID SWITCH MEANS, MEANS FOR ROTATING SAID CAM SHAFT AND TIMING MEANSFOR INTERMITTENTLY ACTUATING SAID ROTATING MEANS, SAID TIMING MEANSINCLUDING AN ACTUATOR COIL FOR ACTUATING SAID ROTATING MEANS, A NEGATIVERESISTANCE DIODE CONNECTED IN SERIES WITH SAID ACTUATOR COIL, SAID DIODEHAVING A PREDETERMINED SWITCHING VOLTAGE, A CAPACITOR CONNECTED IN APARALLEL CIRCUIT WITH THE ACTUATOR COIL AND DIODE, SAID CAPACITOR BEINGCAPABLE OF BEING CHARGED TO A VOLTAVE GREAT ENOUGH TO EXCEQED THESWITCHING VOLTAGE OF SAID DIODE, A RECTIFIER CONNECTED IN SERIES WITHSAID FIRST SWITCH MEANS AND ONE SIDE OF SAID PARALLEN CIRCUIT ANDORIENTED TO PREVENT FLOW OF CURRENT THROUGH SAID DIODE BEFORE SAID DIODEREACHES ITS SWITCHING VOLTAGE, CIRCUIT MEANS CONNECTED TO THE OTHERSIDES OF SAID PARALLEL CIRCUIT AND SAID FIRST AND SECOND LOADS FORCOMPLETING A CIRCUIT WITH SAID POWER SUPPLY, SAID PEAK OUTPUT VOLTAGESOF SAID POWER SUPPLY BEING GREATER THAN THE SWITCHING VOLTAGE OF SAIDDIODE FOR SELECTIVELY SUPPLYING ENERGY TO SAID RECTIFIER AND SAIDPARALLEL CIRCUIT FOR REPEATEDLY OPERATING SAID ACTUATOR COIL AT ONEFREQUENCY WHEN SAID FIRST SWITCH MEANS IS ENGAGED WITH SAID FIRSTCONTACT AND AT ANOTHER FREQUENCY WHEN SAID FIRST SWITCH MEANS IS ENGAGEDWITH SAID SECOND CONTACT.